Wireless display devices will likely become very common in the near future. In order to use these wireless display devices, a communication protocol must be used to send the video information from the video origination device to the display device. The quality of service (QoS) requirements for wireless display applications can vary, but in general can be quite demanding. Many users have become accustomed to a higher quality of video images (e.g., improved color depth, screen refresh rate, and screen resolution). These higher quality video images, however, only increase the QoS demands further. For example, a high-definition multimedia interface (HDMI) connection requires 3 Gbps of bandwidth with a latency of less than 16.6 ms.
Moreover, many video streams use a content protection protocol, such as high-bandwidth digital content protection (HDCP), to protect the video stream from unauthorized copying. These content protection protocols can require a low latency message exchange to authenticate a receiving device (e.g., display device) before a stream is transmitted to the receiving device. HDCP, for example, has a round trip time (RTT) protocol that requires a receiving device to respond to a challenge message (RTT Challenge) with an appropriate response (RTT Response) within a defined latency period. In HDCP, the RTT Response message must be received within either 1) less than 1 ms—allowing 1023 tries or 2) less than 7 ms—allowing 3 retries. These low latency requirements are used to verify that the receiving device is nearby the video source. If the receiving device cannot meet the latency period within the number of tries provided, the video source will not send the video information to the receiving device and the video session is terminated.
These requirements are typically not difficult to meet when the video source is nearby to and has a wired connection with the receiving device. Wireless coupling, however, is typically much slower than wired coupling. Thus, the latency requirements can be difficult to meet when the display device is wirelessly coupled to the video source.